Do US sanctions on Russia threaten Nasa's space programme?

In July, President Obama matched the EU's latest round of sanctions on Russia over the crisis in Ukraine.

Many of them target powerful people close to President Putin who are some of Russia's richest businessmen, but one unexpected victim may be the US space programme. Nasa scientists have been ordered to suspend collaboration with their Russian counterparts.

So what does it mean for a relationship that has been nurtured since the Cold War? And what are the long-term implications for future space programmes?